Track background activity
As soon as your computer connects to the Internet, applications often have permission to send any information wherever they need to. Little Snitch takes note of this activity and allows you to decide for yourself what happens with this data.

Control your network
Choose to allow or deny connections, or define a rule how to handle similar, future connection attempts. Little Snitch runs inconspicuously in the background and it can even detect network-related activity of viruses, trojans, and other malware.

Note: This is a public beta version, only macOS High Sierra users try. This license expires on October 10, 2017

WHAT’S NEW

Version 4.0 Public Beta 1:
Compatibility with macOS High Sierra

This version is compatible with the beta version of macOS High Sierra 10.13.
During the Installation of Little Snitch on macOS High Sierra you may see an error message: “System Extension Blocked”. This is a new security mechanism in High Sierra, requiring you to explicitly allow the installation of a third party system extension. To complete the installation of Little Snitch you have to allow loading the extension in System Preferences > Security & Privacy > General.
There’s a known issue in the map view of Network Monitor causing connection endpoints to be shown twice.

Network Monitor

Fixed a possible crash when zooming to a particular map region in the course of clicking a connection in the list.
Added further time interval filter options for showing only connections from the last week or the last 30 days.
The properties shown in the Summary Inspector (denied, unconfirmed, incoming) now correctly correlate to the corresponding filter options.
Improved pinch-zooming in map: The zooming no longer stops when clusters are expanded into their sites.
Updated GeoIP database. Network Monitor should now know more locations for IP addresses.